1. Field of the Invention
The present invention relates to a control device for an internal combustion engine.
2. Related Art
There is known an internal combustion engine in which a target intake air amount is calculated, an intake pipe pressure, which is a pressure in an intake passage downstream of a throttle valve, is estimated on the basis of a throttle opening, a target throttle opening required for making the actual intake air amount equal to the target intake air amount, is calculated on the basis of the estimated intake pipe pressure, and the throttle valve is driven by an actuator so that the actual throttle opening is made equal to the target throttle opening (see Japanese Unexamined Patent Publication No. 5-65845).
There is a limit in the changing rate or the changeable amount of the throttle opening by the actuator. Therefore, when the engine is rapidly accelerated and thereby the target throttle opening increases greatly, for example, there may be a case in which the actual throttle opening is not made equal to the target throttle opening, or the target throttle opening is not realized. However, the above-mentioned engine considers that the actual throttle opening is made equal to the target value, and then calculates the intake pipe pressure on the basis of the target throttle opening. As a result, there may be a case in which it is impossible to accurately estimate the intake pipe pressure and, therefore, it is impossible to accurately calculate the target throttle opening.